﻿using System.Web.Security;
using System.Security.Cryptography;
using System.Text;
using System.IO;
using System;
using System.Runtime.InteropServices;
namespace EncryptHelper
{
    /// <summary> 
    /// EncryptHelper 来自 www.Admin10000.com 
    /// 
    /// </summary> 
    public class Encrypt
    {
        // 提供8个字符作为DES密钥（程序自动截取前8个字符） 
        private static string key = "GreatGFIYASAKA";

        /// <summary>
        /// DES对称加密解密的密钥
        /// </summary> 
        public static string Key
        {
            get
            {
                return key;
            }
            set
            {
                key = value;
            }
        }

        /// <summary>
        /// MD5 加密（不可逆加密）
        /// </summary>
        /// <param name="pass">要加密的原始字串</param>
        /// <returns></returns> 
        public static string MD5Encrypt(string pass)
        {
            System.Security.Cryptography.MD5 md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
            byte[] bytResult = md5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(pass));
            md5.Clear();
            string strResult = BitConverter.ToString(bytResult);
            strResult = strResult.Replace("-", "");
            return strResult;
            /* 另一种方法
            pass = FormsAuthentication.HashPasswordForStoringInConfigFile(pass, "MD5");
            return pass;
            */
        }

        /// <summary>
        /// SHA1 加密（不可逆加密）
        /// </summary>
        /// <param name="pass">要加密的原始字串</param>
        /// <returns></returns> 
        public static string SHA1Encrypt(string pass)
        {
            System.Security.Cryptography.SHA1 sha1 = new System.Security.Cryptography.SHA1CryptoServiceProvider();
            byte[] bytResult = sha1.ComputeHash(System.Text.Encoding.UTF8.GetBytes(pass));
            sha1.Clear();
            string strResult = BitConverter.ToString(bytResult);
            strResult = strResult.Replace("-", "");
            return strResult;
            /* 另一种方法
            pass = FormsAuthentication.HashPasswordForStoringInConfigFile(pass, "SHA1");
            return pass;
            */
        }

        /// <summary>
        /// DES加密字符串
        /// </summary>
        /// <param name="encryptString">待加密的字符串</param>
        /// <returns>加密成功返回加密后的字符串，失败返回源串</returns> 
        public static string DESEncrypt(string encryptString)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(key.Substring(0, 8));
                byte[] rgbIV = rgbKey;
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                cStream.Close();
                return Convert.ToBase64String(mStream.ToArray());
            }
            catch
            {
                return encryptString;
            }
        }

        /// <summary>
        /// DES解密字符串
        /// </summary>
        /// <param name="decryptString">待解密的字符串</param>
        /// <returns>解密成功返回解密后的字符串，失败返源串</returns> 
        public static string DESDecrypt(string decryptString)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(key.Substring(0, 8));
                byte[] rgbIV = rgbKey;
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                cStream.Close();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return decryptString;
            }
        }

        /// <summary>
        /// 将普通字符串编码为BASE64字串
        /// </summary>
        /// <param name="str">源字符串</param>
        /// <returns></returns> 
        public static string Base64Encode(string str)
        {
            return Convert.ToBase64String(Encoding.UTF8.GetBytes(str));
        }

        /// <summary>
        /// 解码BASE64字串
        /// </summary>
        /// <param name="str">Base64字串</param>
        /// <returns></returns> 
        public static string Base64Decode(string base64Str)
        {
            return Encoding.UTF8.GetString(Convert.FromBase64String(base64Str));
        }


        public static string AESDecrypt(string text)
        {
            string strOut = "";
            try
            {
                StringBuilder sbOutput = new StringBuilder();
                StringBuilder sbInput = new StringBuilder();
                sbInput.Append(text);
                IntPtr cur = Marshal.StringToHGlobalAnsi(text);
                int i = AES.DecryptAES(sbOutput, sbInput);

                if (i > 0 && sbOutput.ToString().Length>0)
                {
                    strOut = sbOutput.ToString().Substring(0, 1);
                }
            }
            catch (Exception ex)
            {

            }
            return strOut;
        }

    }
}